Heat control device for motor vehicle and methods using same

ABSTRACT

The apparatus comprises a heat pump ( 12 ) having a main refrigerant circuit ( 14 ) taking heat from a cold source ( 16 ) and transferring it to a hot source ( 18 ), and a cooling circuit ( 48 ) for cooling an exothermal part, such as an engine, the cooling circuit being connected to a cooling heat exchanger ( 50 ). The cold source ( 16 ) has a first refrigerant/coolant heat exchanger ( 24 ) thermally coupling the main circuit to a first secondary coolant circuit ( 26 ) capable of being selectively connected to an “outside” heat exchanger ( 30 ), to a “cold” heat exchanger ( 32 ), and to the cooling heat exchanger ( 50 ). The hot source ( 18 ) has a second refrigerant/coolant heat exchanger ( 34 ) thermally coupling the main circuit ( 14 ) to a second secondary coolant circuit ( 36 ) capable of being selectively connected to the outside heat exchanger ( 30 ), to a “hot” heat exchanger ( 39 ), and to the cooling heat exchanger ( 50 ). The invention is applicable to air conditioning a vehicle cabin.

[0001] The present invention relates to temperature regulation apparatusfor a motor vehicle, and to methods of implementing the apparatus.

[0002] The invention applies in particular to air conditioning a vehiclecabin.

[0003] The state of the art, and in particular FR-2 697 210, disclosestemperature regulation apparatus for a motor vehicle of the typecomprising:

[0004] a heat pump comprising a main compression circuit for arefrigerant fluid taking heat from a cold source to transfer it to a hotsource; and

[0005] cooling means for cooling an exothermal part of the vehicle, thecooling means comprising a cooling circuit for a liquid coolantconnected to a cooling heat exchanger;

[0006] the cold source or the hot source having a refrigerant/coolantheat exchanger thermally coupling the main refrigerant circuit to asecondary circuit for a liquid coolant, the secondary circuit beingcapable of being selectively connected to at least two heat exchangers.

[0007] The compression circuit generally comprises an evaporator in heatexchange with the cold source, and a condenser in heat exchange with thehot source, these elements being connected together by a compressor andan expander. The refrigerant vaporizes in the evaporator, thereby takingheat from the cold source. The compressor draws in the vaporizedrefrigerant and delivers it to the condenser which is cooled by heatexchange with the hot source, and in which the refrigerant condenses.The expander allows the refrigerant in the liquid state to pass to theevaporator by reducing its pressure.

[0008] The heat pump may be used either to heat a space or a part, orelse to cool said space or said part.

[0009] In FR-2 697 210, the hot source comprises a firstrefrigerant/coolant heat exchanger thermally coupling the mainrefrigerant circuit to a first secondary coolant circuit, and the hotsource comprises a second refrigerant/coolant heat exchanger thermallycoupling the main refrigerant circuit to a second secondary coolantcircuit. The secondary circuits are capable of being selectivelyconnected via appropriate valves to an outside heat exchanger placed inthe vehicle engine compartment, and to an inside heat exchanger placedinside the vehicle cabin. By acting on the valves, it is possible to usethe heat pump either to cool the vehicle cabin, in this first case theheat source is the outside heat exchanger and the cold source is theinside heat exchanger, or else to heat the cabin, in this second casethe hot source is the inside heat exchanger and the cold source is theoutside heat exchanger.

[0010] It will be observed that in the second case, the performance ofthe heat pump is limited by the temperature of the outside air. In thecold season, the temperature of the outside air is not sufficient toobtain satisfactory efficiency for the heat pump when it is used for thepurpose of heating the cabin. In addition, frosting of the cold sourcein the cold season can harm the operating performance of the heat pump.

[0011] Furthermore, the reversibility of the outside and inside heatexchangers (each used either as a hot source or as a cold source) leadsessentially to the following two drawbacks:

[0012] 1) the performance of each heat exchanger is limited by the factthat it cannot be optimized for specific operation of the heat exchangereither as a hot source or else as a cold source; and

[0013] 2) it is difficult to control the humidity of the air in thevicinity of the inside heat exchanger.

[0014] The second drawback is particularly troublesome when airconditioning the vehicle cabin in mid-season. Under such circumstances,the inside heat exchanger is likely to alternate frequently between itscabin-refrigerating and cabin-heating modes of operation. Thus, inrefrigerating mode, the inside heat exchanger picks up water. When itswitches to heating mode, the water accumulated while in refrigeratingmode is exhausted into the cabin by evaporation. FR-2 697 210 disposesmitigating that drawback by means of an auxiliary heat exchangerarranged in the vicinity of the inside heat exchanger. Nevertheless,that auxiliary heat exchanger is not functional under certaincircumstances, and in particular for mid-seasons temperatures of around15° C.

[0015] A particular object of the present invention is to optimize theperformance of temperature regulation apparatus having a heat exchanger,in particular when it is used for heating or refrigerating a motorvehicle cabin or when it is used for regulating the temperature of amotor for propelling the vehicle.

[0016] To this end, the invention provides temperature regulationapparatus for a motor vehicle, the apparatus being of the above-citedtype and being characterized in that the secondary circuit is capable ofbeing selectively connected to the cooling heat exchanger, to an“outside” heat exchanger, and to a “hot” or “cold” heat exchanger.

[0017] Characteristics of various embodiments of the apparatus are asfollows:

[0018] the cold source comprises a first refrigerant/coolant heatexchanger thermally coupling the main refrigerant circuit to a firstsecondary coolant circuit capable of being selectively connected to thecooling heat exchanger, to the outside heat exchanger, and to a “cold”heat exchanger; and the hot source comprises a secondrefrigerant/coolant heat exchanger thermally coupling the mainrefrigerant circuit to a second secondary coolant circuit capable ofbeing selectively connected to the cooling heat exchanger, to theoutside heat exchanger, and to a “hot” heat exchanger;

[0019] the first and second secondary circuits are capable of beingconnected to the cooling circuit via:

[0020] a first bypass valve of the three-port type comprising a firstport connected to the outlets of the first and secondrefrigerant/coolant heat exchangers, a second port connected to theinlet of the outside heat exchanger, and a third port connected to abranch of the cooling circuit upstream from the cooling heat exchanger;and

[0021] a second bypass valve of the three-port type comprising a firstport connected to the inlets of the first and second refrigerant/coolantheat exchangers, a second port connected to a branch of the coolingcircuit downstream from the cooling heat exchanger, and a third portconnected to the outlet of the outside heat exchanger;

[0022] the first and second secondary circuits are suitable for beingconnected to the cooling circuit via:

[0023] a first bypass valve of the two-port type comprising a first portconnected to a branch of the cooling circuit upstream from the coolingheat exchanger, and a second port connected to branches of the first andsecond secondary circuits upstream from the outside heat exchanger; and

[0024] a second bypass valve of the two-port type comprising a firstport connected to a branch of the cooling circuit downstream from thecooling heat exchanger, and a second port connected to branches of thefirst and second secondary circuits downstream from the outside heatexchanger;

[0025] the cooling heat exchanger is a coolant/air heat exchanger;

[0026] the coolant liquid of the cooling circuit is a mixture of waterand antifreeze;

[0027] the outside heat exchanger and the cooling heat exchanger areinterconnected so as to form a single module suitable for beingpreassembled prior to being mounted in the vehicle; and

[0028] the exothermal part is a motor.

[0029] The invention also provides a method of implementing theapparatus as defined above, the method being characterized in that thecoolant liquid of at least one of the secondary circuits is caused tocirculate both through the outside heat exchanger and through thecooling heat exchanger.

[0030] The invention also provides a method of implementing theapparatus as defined above, the method being characterized in that thecoolant liquid of the cooling circuit is caused to circulate boththrough the outside heat exchanger and the cooling heat exchanger.

[0031] The invention will be better understood on reading the followingdescription given purely by way of example and made with reference tothe accompanying drawings, in which:

[0032]FIGS. 1 and 2 are diagrammatic views in respective first andsecond configurations of use of motor vehicle temperature regulationapparatus constituting a first embodiment of the invention;

[0033]FIG. 3 is a fragmentary view of the temperature regulationapparatus shown in the preceding figures, showing the apparatus in athird configuration of use; and

[0034]FIG. 4 is a view similar to FIG. 3 showing motor vehicletemperature regulation apparatus in a second embodiment of theinvention.

[0035] FIGS. 1 to 3 show motor vehicle temperature regulation apparatusconstituting a first embodiment of the invention, and given overallreference 10.

[0036] In the description below, two parts are said to be thermallycoupled together when they exchange heat between each other by means ofa suitable heat exchanger.

[0037] The temperature regulation apparatus 10 comprises a heat pump 12having a main refrigerant circuit 14 of the compression type taking heatfrom a cold source 16 and transferring at least some of it to a hotsource 18.

[0038] The cold and hot sources 16 and 18 are connected together by acompressor 20 (electrically or mechanically driven) and an expandervalve 22. The refrigerant vaporizes taking heat from the cold source 16the compressor 20 draws in the vaporized refrigerant and delivers it tothe hot source where it condenses and cools. The expander valve 22allows the refrigerant to pass in liquid form towards the cold source 16by lowering its pressure. The refrigerant circulates around the circuit14 in the direction marked by arrows in FIG. 1.

[0039] The cold source 16 comprises a first refrigerant/coolant heatexchanger 24 thermally coupling the main refrigerant circuit 14 to afirst secondary circuit 26 for liquid coolant. This circuit includes apump 28 for circulating the liquid coolant, which pump is connected tothe inlet of the first heat exchanger 24.

[0040] The first secondary circuit 26 is capable of being selectivelyconnected to an “outside” heat exchanger 30 and to a “cold” heatexchanger 32.

[0041] In the example shown in FIGS. 1 to 3, the outside heat exchanger30 is a coolant/air heat exchanger placed in the engine compartment M ofthe vehicle, and the cold heat exchanger 32 is a coolant/air heatexchanger placed in the vehicle cabin H.

[0042] The hot source 18 has a second refrigerant/coolant heat exchanger34 thermally coupling the main refrigerant circuit 14 to a secondsecondary circuit 36 for liquid coolant. This second secondary circuitcomprises a pump 38 for circulating the liquid coolant, which pump isconnected to the inlet of the second heat exchanger 34.

[0043] The second secondary circuit 36 is capable of being selectivelyconnected to the outside heat exchanger 30 and to a “hot” heat exchanger39.

[0044] In the example shown in FIGS. 1 to 3, the hot heat exchanger 39is a coolant/air heat exchanger placed in the vehicle cabin H.

[0045] A conventional fan (not shown in the figures) serves to cause aflow of air to circulate through the cold and hot heat exchangers 32 and39.

[0046] The heat pump 12 connected to the first and second heatexchangers 24 and 34 is located, for example, in the engine compartmentof the vehicle.

[0047] The refrigerant circulating in the main circuit is ofconventional type. This refrigerant is selected, for example, fromchlorine and fluorine derivatives of methane and of ethane (Freon),hydrocarbons, ammonia, and carbon dioxide. The coolant liquidcirculating in the first and second secondary circuits 26 and 36 ispreferably a mixture of water and antifreeze (glycol).

[0048] The two secondary coolant circuits 26 and 36 are connected to theoutside, cold, and hot heat exchangers 30, 32, and 39 respectively bymeans of a three-port valve 40 of the first secondary circuit, athree-port valve 42 of the second secondary circuit, and a three-portvalve 44 common to both secondary circuits.

[0049] The three-port valve 40 of the first secondary circuit 26 isconnected to the outlet of the first refrigerant/coolant heat exchanger24 of the cold source, to the inlet of the outside heat exchanger 30,and to the inlet of the cold heat exchanger 32.

[0050] The valve 42 of the second secondary circuit 36 is connected tothe outlet of the second refrigerant/coolant heat exchanger 34 of thehot source, to the inlet of the outside heat exchanger 30, and to theinlet of the hot heat exchanger 39.

[0051] The valve 44 common to the first and second secondary coolantcircuits 26 and 36 is connected to the inlet of the firstrefrigerant/coolant heat exchanger 24 of the cold source, to the inletof the second refrigerant/coolant heat exchanger 34 of the hot source,and to the outlet of the outside heat exchanger 30.

[0052] The valves 40 to 44 are controlled by conventional electrical,mechanical, thermomechanical, or pneumatic means.

[0053] The temperature regulation apparatus 10 also comprises means forcooling an exothermal part of the vehicle such as a motor for thevehicle as in the example described. This motor for propelling thevehicle is preferably of the heat engine type. Nevertheless, in avariant, the motor could be of some other type, in particular it couldbe an electric motor.

[0054] The engine cooling means comprise a cooling liquid circuit 48connected to a cooling heat exchanger 50.

[0055] In the example shown in the figures, the cooling heat exchanger50 is a coolant/air heat exchanger preferably located in the enginecompartment M of the vehicle. A conventional fan (not shown in thefigures) serves to cause a flow of air to pass through this cooling heatexchanger 50.

[0056] The coolant liquid circulating in the cooling circuit 48 ispreferably a mixture of water and antifreeze (glycol).

[0057] The first and second secondary circuits 26 and 36 are designed tobe connected in certain configurations of use of the apparatus 10 to thecooling heat exchanger 50.

[0058] For this purpose, in the first embodiment of the invention, thefirst and second secondary circuits 26 and 36 are capable of beingconnected to the cooling circuit via the following means.

[0059] A first bypass valve 52 of the three-port type has a first portconnected to the outlets of the first and second refrigerant/coolantheat exchangers 24 and 34, a second port connected to the inlet of theoutside heat exchanger 30, and a third port connected to a branch of thecooling circuit 48 upstream from the cooling heat exchanger 50.

[0060] A second bypass valve 54 of the three-port type has a first portconnected to the inlets of the first and second refrigerant/coolant heatexchangers 24 and 34, a second port connected to a branch of the coolingcircuit 48 downstream from the cooling heat exchanger 50, and a thirdport connected to the outlet of the outside heat exchanger 30.

[0061] The bypass valves 52 and 54 are controlled by conventionalelectrical, mechanical, thermomechanical, or pneumatic means.

[0062]FIG. 1 shows the configuration of the temperature regulationapparatus 10 in vehicle cabin refrigerating mode. In this case, thevalves 40 to 44 are set so as to connect the first secondary coolantcircuit 26 to the cold heat exchanger and the second secondary coolantcircuit 36 to the outside heat exchanger 30.

[0063] At the same time, the bypass valves 52 and 54 are set so as tocause the coolant of the second secondary circuit 36 to circulate boththrough the outside heat exchanger 30 and through the cooling heatexchanger 50. This setting of the bypass valves 52 and 54 is preferablyestablished while the cooling means that are generally under the controlof a thermostat are deactivated, so that the flow of cooling liquid inthe circuit 48 at that time is zero. It should be observed that thecooling means are deactivated while the vehicle engine is relativelycold, particularly during a longer or shorter period following startingof the engine.

[0064] The coolant of the first secondary circuit 26 takes heat from thecabin via the cold heat exchanger 32, and delivers it to the vaporizedrefrigerant via the first refrigerant/coolant heat exchanger 24.

[0065] The coolant of the second secondary circuit 36 takes heat fromthe condensed refrigerant via the second refrigerant/coolant heatexchanger 34 and delivers it to the outside of the vehicle via theoutside heat exchanger 30 and the cooling heat exchanger 50.

[0066] The cooling heat exchanger 50 adds to the heat exchange area ofthe outside heat exchanger 30 so the operation of the heat pump isoptimized by heat being exhausted more efficiently from the hot source18 by the coolant circulating in the second secondary circuit 36 andthrough these heat exchangers 30 and 50.

[0067]FIG. 2 shows the apparatus 10 in a cabin heating configuration. Inthis configuration, the valves 40 to 44 are set in such a manner as toconnect the first secondary coolant circuit 26 to the outside heatexchanger 30 and the second secondary coolant circuit 36 to the hot heatexchanger 39.

[0068] Furthermore, the bypass valves 52 and 54 are set in a manneranalogous to that shown in FIG. 1 to cause the coolant of the firstsecondary circuit 26 to flow both through the outside heat exchanger 30and through the cooling heat exchanger 50. This setting of the bypassvalves 52 and 54 is preferably established while the cooling means aredeactivated, so that, at that time, the flow rate of cooling liquidthrough the circuit 48 is zero.

[0069] The coolant of the first secondary circuit 26 takes heat fromoutside the vehicle via the outside heat exchanger 30 and the coolingheat exchanger 50, and delivers it to the vaporized refrigerant via thefirst refrigerant/coolant heat exchanger 24.

[0070] The coolant of the second secondary circuit 36 takes heat fromthe condensed refrigerant via the second refrigerant/coolant heatexchanger 34 and delivers it to the cabin via the hot heat exchanger 39.

[0071] Since the cooling heat exchanger 50 adds to the heat exchangearea of the outside heat exchanger 30, the operation of the heat pump isoptimized by the coolant circulating in the first secondary circuit 26and through both heat exchangers 30 and 50, thereby taking heat moreefficiently from the outside air. Thus, the risks of the outside heatexchanger 30 frosting in the cold season are reduced.

[0072] Naturally, the valves 40 to 44 can be set to occupyconfigurations that are intermediate relative to the cabin-cooling andcabin-heating configurations shown in FIGS. 1 and 2, for example inorder to accelerate cabin heating while contributing to controlling therelative humidity therein.

[0073]FIG. 3 shows the apparatus 10 in a cabin configuration where thevalves 40 to 44 are set in a manner similar to FIG. 2 (cabin heating).Nevertheless, in this configuration, the engine cooling means areactive: the cooling liquid is circulating in the cooling circuit 48. Asa result, the bypass valves 52 and 54 are set so as to isolate thesecondary circuit 26 and the outside heat exchanger 30 from the coolingcircuit 48 and the cooling heat exchanger 50.

[0074] In a configuration that is not shown, the valves 40 to 44 can beset in a manner similar to FIG. 1 (cabin cooling) and the bypass valves52 and 54 in a manner similar to FIG. 3. This configuration in which thesecondary circuit 26 and the outside heat exchanger 30 are isolated fromthe cooling circuit 48 and the cooling heat exchanger 50 is establishedwhile the engine cooling means are activated.

[0075]FIG. 4 shows temperature regulation apparatus in a secondembodiment of the invention. In this figure, elements analogous to thoseof the preceding figures, are designated by identical references.

[0076] In this embodiment, the first and second secondary circuits 26and 36 are capable of being connected to the cooling circuit 48 via thefollowing means.

[0077] A first bypass valve 56 of the two-port type has a first portconnected to a branch of the cooling circuit 48, upstream from thecooling heat exchanger 50, and a second port connected to branches ofthe first and second secondary circuits 26 and 36 upstream from theoutside heat exchanger 30.

[0078] A second bypass valve 58 of the two-port type has a first portconnected to a branch of the cooling circuit 48 downstream from thecooling heat exchanger 50, and a second port connected to branches ofthe first and second secondary circuits 26 and 36 downstream from theoutside heat exchanger 30.

[0079] The bypass valves 56 and 58 are controlled by conventionalelectrical, mechanical, thermomechanical, or pneumatic means.

[0080] The bypass valves 56 and 58 may be set out as to obtainconnection (or isolation) configurations for the secondary circuits 26and 36 and the cooling circuit 48 relative to one another that areanalogous to the configurations shown in FIGS. 1 to 3.

[0081] Nevertheless, in this second embodiment of the invention, thebypass valves 56 and 58 may also be set so as to cause the coolant ofthe cooling circuit 48 to flow both through the outside heat exchanger30 and through the cooling heat exchanger 50. This setting isadvantageous when it is desired to provide effective cooling of anengine that is being subjected to exceptional overheating, because inthis configuration the outside heat exchanger 30 adds to the heatexchange area of the cooling heat exchanger 50.

[0082] It may be observed that the outside and cooling heat exchangers30 and 50 may be arranged in the engine compartment in various ways. Inparticular, these two heat exchangers 30 and 50 can be arranged eitherone behind the other (in a stacked configuration) so that theirprojections onto a plane substantially perpendicular to the direction ofthe flow of air passing through them overlaps at least in part, or elsethey can be arranged one beside the other (mosaic configuration) so thattheir projections onto a plane substantially perpendicular to the flowdirection of the air passing through them do not overlap.

[0083] Furthermore, the outside and cooling heat exchangers 30 and 50may be interconnected by the bypass valves so as to form a single modulethat can be preassembled prior to being mounted in the enginecompartment.

[0084] The invention is not limited to the embodiments described above.In particular, in the first embodiment shown in FIGS. 1 to 3, it ispossible to provide bypass valves 52, 54 suitable for being set so as tocause the coolant of the cooling circuit 48 to flow both through theoutside heat exchanger 30 and through the cooling heat exchanger 50.

1/ Motor vehicle temperature regulation apparatus of the typecomprising: a heat pump (12) comprising a main compression circuit (14)for a refrigerant fluid taking heat from a cold source (16) to transferit to a hot source (18); and cooling means for cooling an exothermalpart of the vehicle, the cooling means comprising a cooling circuit (48)for a liquid coolant connected to a cooling heat exchanger (50); thecold source (16) or the hot source (18) having a refrigerant/coolantheat exchanger (24, 34) thermally coupling the main refrigerant circuit(14) to a secondary circuit (26, 36) for a liquid coolant, the secondarycircuit being capable of being selectively connected to at least twoheat exchangers; the apparatus being characterized in that the secondarycircuit (26, 34) is capable of being selectively connected to thecooling heat exchanger (50), to an “outside” heat exchanger (30), and toa “hot” or “cold” heat exchanger (32, 39). 2/ Apparatus according toclaim 1, characterized in that: the cold source (16) comprises a firstrefrigerant/coolant heat exchanger (24) thermally coupling the mainrefrigerant circuit to a first secondary coolant circuit (26) capable ofbeing selectively connected to the cooling heat exchanger (50), to theoutside heat exchanger (30), and to a “cold” heat exchanger (32); andthe hot source (18) comprises a second refrigerant/coolant heatexchanger (34) thermally coupling the main refrigerant circuit (14) to asecond secondary coolant circuit (36) capable of being selectivelyconnected to the cooling heat exchanger (50), to the outside heatexchanger (30), and to a “hot” heat exchanger (39). 3/ Apparatusaccording to claim 2, characterized in that the first and secondsecondary circuits (26, 36) are capable of being connected to thecooling circuit (48) via: a first bypass valve (52) of the three-porttype comprising a first port connected to the outlets of the first andsecond refrigerant/coolant heat exchangers (24, 34), a second portconnected to the inlet of the outside heat exchanger (30), and a thirdport connected to a branch of the cooling circuit (48) upstream from thecooling heat exchanger (50); and a second bypass valve (54) of thethree-port type comprising a first port connected to the inlets of thefirst and second refrigerant/coolant heat exchangers (24, 34), a secondport connected to a branch of the cooling circuit (48) downstream fromthe cooling heat exchanger (50), and a third port connected to theoutlet of the outside heat exchanger (30). 4/ Apparatus according toclaim 2, characterized in that the first and second secondary circuits(26, 36) are suitable for being connected to the cooling circuit (48)via: a first bypass valve (56) of the two-port type comprising a firstport connected to a branch of the cooling circuit (48) upstream from thecooling heat exchanger (50), and a second port connected to branches ofthe first and second secondary circuits (26, 36) upstream from theoutside heat exchanger (30); and a second bypass valve (58) of thetwo-port type comprising a first port connected to a branch of thecooling circuit (48) downstream from the cooling heat exchanger (50),and a second port connected to branches of the first and secondsecondary circuits (26, 36) downstream from the outside heat exchanger(30). 5/ Apparatus according to any preceding claim, characterized inthat the cooling heat exchanger (50) is a coolant/air heat exchanger. 6/Apparatus according to any preceding claim, characterized in that thecoolant liquid of the cooling circuit (48) is a mixture of water andantifreeze. 7/ Apparatus according to any preceding claim, characterizedin that the outside heat exchanger (30) and the cooling heat exchanger(50) are interconnected so as to form a single module suitable for beingpreassembled prior to being mounted in the vehicle. 8/ Apparatusaccording to any preceding claim, characterized in that the exothermalpart is a motor. 9/ A method of implementing the apparatus according toany preceding claim, characterized in that the coolant liquid of atleast one of the secondary circuits (26, 36) is caused to circulate boththrough the outside heat exchanger (30) and through the cooling heatexchanger (50). 10/ A method of implementing the apparatus according toany one of claims 2 and 5 to 6 taken in combination with claim 4,characterized in that the coolant liquid of the cooling circuit (48) iscaused to circulate both through the outside heat exchanger (30) and thecooling heat exchanger (50).